Table 1.

Demographics and lymph node distribution of training and two validation cohorts.

Characteristics	Training cohort LN = 159	Internal validation cohort LN = 69	External validation cohort LN = 60	p value
Gender (from M/F patients)	113/46	47/22	40/20	0.789
Age (years)	64.4 ± 9.0	65.2 ± 8.7	67.2 ± 6.9	0.090
Lung cancer _pathology (ADA/ SQCC/other types of NSCLC)	93/49/17	46/17/6	29/22/9	0.333
LN station				0.153
1R/1L/2R/2L/3A/4R/4L	2/1/4/0/1/25/5	1/1/0/1/0/9/2	2/0/0/0/2/9/3
5/6/7/8/9L/10R/10L	10/5/32/1/1/33/17	1/1/14/0/1/15/9	2/1/8/0/1/9/4
11R/11L/12R/12L/13R	11/11/0/0/0	11/2/0/1/0	8/6/2/1/2
Means of obtaining pathology (surgery/TBNA)	127/32	51/18	48/12	0.572

LN, lymph node; M, man; F, female; ADA, adenocarcinoma; SQCC, squamous-cell carcinoma, NSCLC, non-small cell lung cancer.